1. Field of the Invention
The present invention relates to a washing unit in the printing unit of rotary printing presses, which washing unit includes a driven brush roller. The brush roller can be brought into contact against the cylindrical surface of a cylinder to be cleaned. The washing unit also includes a cleaning agent feed device, a wiper on the brush roller and a housing to catch the dirty washing fluid ejected from, or sprayed off by, the brush roller.
2. Background Information
In a similar known device (German Utility Model No. 94 03 228), the brush roller is provided below the cylindrical surface of a cylinder to be cleaned and is enclosed by a housing. The cleaning fluid in this known realization is sprayed into the brush roller by means of a spray tube which spray tube extends into the area occupied by the rotating bristles. There is also a wiper which is located ahead of the spray tube, seen in the direction of rotation of the brush roller, and which deflects the bristles and causes them to spring back, so that the dirty cleaning fluid is ejected or sprayed off. This known washing device can be used without problems in the lower portion of the cylinder to be cleaned. In the design of a printing unit, however, the space available or the layout of the equipment does not always make it possible to install the washing device in this location. For example, if such a washing device must be located above the cylinder to be cleaned, because such a location is necessitated by the space available in the machine, the dispensing of the correct quantity of washing fluid can lead to problems, i.e. the feed tubes can inadvertently run dry, or dripping fluid can result in problems with the printing process. If the feed tubes run dry, there will also be problems in the performance of the washing process which result from the failure to dispense the correct or required amount of washing agent. The location of valves on the spray nozzles would make the washing device significantly more expensive.